如何显示特定的阵列组合？

i want to display following array in output as 246,357 that is donot process first subarray and also the remaining subarray combination should be like $array[1][0].$array[2][0].$array[3][0],similarly combination should be $array[1][1].$array[2][1].$array[3][1]

$array=[
          [0,1],
          [2,3],
          [4,5],
          [6,7]
       ];

i have written follwing code but could not bypass first subarray so my output is 0246,1357.plz help.

foreach($array as $n)
{
    $a.=$n[0];
    $b.=$n[1];
}
echo "$a".","."$b";

One way to skip the first element would be to use a flag variable $first:

$first = true;
foreach ($array as $n) {
    if ($first) {
        $first = false;
    } else {
        $a .= $n[0];
        $b .= $n[1];
    }
}

Another way would be to remove the first element from the array, so it will be skipped over:

unset($array[0]);

Or check the key from within the foreach loop:

foreach ($array as $k => $n) {
    if ($k > 0) {
        $a .= $n[0];
        $b .= $n[1];
    }
}

Yet another way would be to use array_shift(), which changes numeric keys in addition to removing the first element:

array_shift($array);

Finally, because your array contains only consecutive integer keys starting from 0, you could just use a normal for loop:

for ($i = 1; $i < count($array); $i++) {
    $a .= $array[$i][0];
    $b .= $array[$i][1];
}

Skip the first sub array by using a regular for loop which starts at offset 1 instead of the foreach loop.

for ($i = 1; $i <= count($array); $i++) {
    $a.=$array[$i][0];
    $b.=$array[$i][1];
}

Alternatives

1. You could also remove the first sub array with array_shift() and use the code you already have.
2. Use a flag as many of the other answers suggests (I think it's over complicated though).

Another code improvement suggestion

The line

echo "$a".","."$b";`

Can be written as

echo "{$a},{$b}";

Which I think is a lot more readable.

This will help you to skip the first array

foreach($array as $key => $n)
{
 if($key>0)
 {
    $a.=$n[0];
    $b.=$n[1];
 }
}

You can use this:-

$flag = true;
foreach ($array as $n) {
    if ($flag==false) {
        $a .= $n[0];
        $b .= $n[1];
    } else {
        $flag = false;
    }
}

Check this anser without any loops :

$array=array(array(0,1),
            array(2,3),
            array(4,5),
            array(6,7)
       );

array_shift($array);
array_unshift($array, null);
$result = array_map("implode",call_user_func_array('array_map', $array));

echo "<pre>";
print_r($result);

Output :

Array
(
    [0] => 246
    [1] => 357
)